Article: Knee Surgery Q

Twins starting catcher Jason Castro went on the DL May 5th with pain in his right knee. Initially, it was reported that Castro underwent a cortisone injection and was hopeful to return to the lineup soon. Unfortunately, after traveling to Vail, CO to see noted orthopedic surgeon Dr. Robert LaPrade, Castro is now scheduled to undergo surgery May 15th to address a meniscus tear. (Update: Now being reported that he underwent more extensive surgery including a meniscus repair and is now out for the season). This will be the third surgery for Castro’s troublesome right knee, according to the Pioneer Press. He sustained an ACL tear along with a meniscus tear in spring training 2011 and underwent surgery, which caused him to miss the entire season. He also underwent arthroscopic surgery on the same knee in September 2013.

Let’s discuss some knee anatomy and some meniscus ‘fun facts’ (Note: these facts may only be considered fun to me…)Question 1: What is the meniscus? What is its function?

The meniscus is a C-shaped cartilage cushion that is positioned between the bones of the knee (the femur and tibia). It has several functions including acting as a shock absorber, a protector of the surface cartilage and a stabilizer of the knee. There are two menisci in each knee- a medial and lateral meniscus. The medial is positioned at the inside of the knee, the lateral to the outside. Both the medial and lateral meniscus increase the surface area of bone contact within the knee when walking/running, thereby spreading out the contact forces over a larger area. This function protects the surface gliding cartilage (called articular cartilage) from being damaged.

Question 2: How is a meniscus torn/damaged?A meniscus can be torn in several ways, but most commonly it is damaged when the knee undergoes an abrupt change of direction and the stress is more than the meniscus can withstand. In the case of Castro, it sounds as though he had some damage to his meniscus in 2011 when he also tore his ACL. A meniscus tear accompanies an ACL tear about 50% of the time. Either the medial or lateral meniscus can be torn, and in some cases both sustain injury.

Question 3: How are meniscus tears assessed?Most commonly an MRI is ordered to look at the meniscus more closely. The meniscus can’t be seen on xrays. There is a device that is similar to a large needle that has a camera inside it that can be inserted into the knee during an office visit to view the meniscus directly, but I don’t have much experience with this device.

Question 4: What types of tears can occur?There are a number of different types of meniscus tears, and there are many tears which don’t fit neatly into a single category as well.

Question 5: What are the treatment options for meniscus tears?There are a number of different options for treatment of meniscus tears. Not every meniscus tear will require surgery- in fact, many people may have a meniscus tear in their knee and not even be aware of it. Anti-inflammatory medication, injections (including cortisone, gel/lubricant, and PRP injections), and physical therapy are among the non-surgical options. When these are not successful (or surgery is deemed necessary early on), knee arthroscopy is performed.During knee arthroscopy, the knee is inflated with fluid and a camera is inserted inside the joint. The structures of the knee can be readily assessed, and tools are used to examine and probe the meniscus, surface cartilage and ligaments. The specifics of the meniscus tear are then evaluated. A decision is then made whether to repair the meniscus or remove the torn portion of meniscus (called a partial meniscectomy). This decision can be complex and is based on a number of factors including the size, location and orientation of the tear, patient-specific factors such as age, weight, health, prior surgery to the knee and others.

Ideally, we would repair all meniscus tears, as removing meniscus can lead to the development of arthritis later on. However, some tears are simply unable to be repaired and must be partially removed. Tears closer to the outer edge of the meniscus have better blood supply are more likely to heal, and thus are better suited to repair.

Question 6: What is the recovery time?This can vary significantly, but for partial removal, most athletes can return to sports between 6-10 weeks after surgery. For repair, the recovery is longer because of the additional time required for the repaired tissue to heal. Typically, a return to sports for a meniscus repair is around 3-5 months.

Question 7: Are there any special circumstances with Castro’s knee?I would say yes. The fact that he has had two prior surgeries on the knee (including an ACL reconstruction) often makes the MRI more challenging to interpret and can complicate decision-making. It is unclear to me if the current meniscus damage is in the same area where he previously had surgery, which can create an already abnormal appearance on MRI. Thus, it is difficult to know whether what appears abnormal on a current MRI is ‘new’ or ‘old’. However, it sounds like he has continued to have intermittent problems over a lengthy amount of time now, and it seems reasonable to go ahead with arthroscopy. One concern is that a tear can enlarge in size over time if left alone (though this is difficult to predict).Dr. LaPrade is a world’s authority on knee problems and I’m sure he will do his best to get Castro back to action quickly and safely.

Yes ... just for everyone to be clear ... John didn't quite post this correctly and this was written by heezy1323, our resident expert on such matters, and not by John Bonnes. In case others didn't already see/read it, heezy posted it to his blog yesterday and it was promoted to an article today. So if you have questions, direct them to heezy and not John.

Hmmm... I was not aware Castro had two prior knee surgeries before. With the third already completed, I wonder if this could shorten his catching career? Not that I think his knee will be like Sam Bradford's, but I do think it could be a concern going forward.

Yes ... just for everyone to be clear ... John didn't quite post this correctly and this was written by heezy1323, our resident expert on such matters, and not by John Bonnes. In case others didn't already see/read it, heezy posted it to his blog yesterday and it was promoted to an article today. So if you have questions, direct them to heezy and not John.

Ugh, yes my apologies to heezy. I posted it initially under his name, but sometime when you edit a story (i fixed a mistake I made) it puts it back to my name. I just hate it when I miss that.

No worries, John. Thank you for the opportunity to contribute. I'm glad folks are finding the posts interesting.

I find these meniscus tears and surgeries interesting, as a high school coach. I have seen a few kids go through these procedures. The one thing that I have witnessed first hand is the fact that every single athlete who has had his meniscus repaired, (which in my career has been 6 of them), every single one of them, 6 for 6, has within weeks of being able to return to competition has re-tore that same meniscus, it has been like clockwork, no athlete that I have had with the repair has made it through the next season without it re tearing. Now on the flip side I have dealt with 8 athletes who have had meniscus removal procedure done, 5 of them were in the first 6 who had the repair the first time, so there is some crossover. Of those athletes all of them were almost back to normal within a couple of weeks? So far in my experience, it doesn't seem like the repair method has done so well for those still competing. Now it is possible that because Castro has probably one of the best doctors because he is an MLB player and all that his might work out better. But it would seem in my limited experience that 6 for 6 meniscus failure is not a good ratio. Especially for a catcher squatting down all of the time. This procedure might be 90 to 100 percent effective for a guy or gal that works in an office and just has to walk around all day. But it seems that to me once the athlete starts to put the same stressors on the injured meniscus it tends to fail again.

I just wanted a more professional opinion, mine is just a layman's opinion from what I have seen happen to my athletes. I am a wrestling coach, so there is a lot of twisting and pounding going on, but it would seem that a catcher would be dealing with a lot of that himself?

I find these meniscus tears and surgeries interesting, as a high school coach. I have seen a few kids go through these procedures. The one thing that I have witnessed first hand is the fact that every single athlete who has had his meniscus repaired, (which in my career has been 6 of them), every single one of them, 6 for 6, has within weeks of being able to return to competition has re-tore that same meniscus, it has been like clockwork, no athlete that I have had with the repair has made it through the next season without it re tearing. Now on the flip side I have dealt with 8 athletes who have had meniscus removal procedure done, 5 of them were in the first 6 who had the repair the first time, so there is some crossover. Of those athletes all of them were almost back to normal within a couple of weeks? So far in my experience, it doesn't seem like the repair method has done so well for those still competing. Now it is possible that because Castro has probably one of the best doctors because he is an MLB player and all that his might work out better. But it would seem in my limited experience that 6 for 6 meniscus failure is not a good ratio. Especially for a catcher squatting down all of the time. This procedure might be 90 to 100 percent effective for a guy or gal that works in an office and just has to walk around all day. But it seems that to me once the athlete starts to put the same stressors on the injured meniscus it tends to fail again.

I just wanted a more professional opinion, mine is just a layman's opinion from what I have seen happen to my athletes. I am a wrestling coach, so there is a lot of twisting and pounding going on, but it would seem that a catcher would be dealing with a lot of that himself?

I thank you in advance for any extra info on this type of situation.

So this is a very complex question/issue- I could probably do a two hour talk about it. No one wants to be inundated with that much ortho info by me, so I'll do my best to summarize.

As discussed in the article above, the meniscus is critical for normal function of many aspects of the knee. This includes stability, cushion and protection of the surface cartilage. Because of the importance of the meniscus, it is critical to try to preserve as much meniscus as possible, as often as possible in order to optimize the long-term function/health of the knee. For example, we know from studies that one of the biggest risk factors for ACL graft failure after reconstruction is having had part of your meniscus removed at the same time as reconstruction. We also know that the greater the amount of meniscus removed, the greater the risk that a person develops arthritis down the road.

Recall, arthritis is thinning or damage to the gliding surface cartilage of the knee (which is different from the meniscus itself). Once damage to the surface cartilage occurs, we don't have a great way to repair or restore the cartilage to normal. (There are some procedures that we have as options, but they are rarely as good as normal cartilage.)

Because of the lack of good options to treat arthritis, especially in young patients, we have become more aggressive over time at attempting to repair meniscus tears in order to prevent this problem.

With regards to stability, think of the meniscus as a chock that you place behind the wheel of a trailer that is parked on a hill to prevent it from rolling away. The meniscus helps stabilize the knee in the same way. As a result, when you remove part of the meniscus during an ACL reconstruction, there is a smaller 'chock' and therefor the ACL sees higher stress and is at greater risk to fail/re-tear.

In addition to our understanding of the function of the meniscus and its importance, we also have developed better tools to perform meniscus repairs more safely and easily.

As a result of the above factors, the number of attempted meniscus repairs has increased dramatically over the past 10-15 years. Any time you increase the number of procedures, the number of failures also increases (by sheer volume).

With respect to your specific examples noted in your post, I do have a couple of thoughts. One is, in young patients (particularly athletes) I am VERY aggressive with trying to repair any meniscus tear, because they are the patients that need their meniscus the most. If it fails, it is of course unfortunate, but removing meniscus that has a chance to heal is a bad idea, IMHO.

A second thought is that there could be some technical factors in play. Studies have shown that technique is critical in repairing these tears, and it is possible that some component of the failure is attributable to this. A surgeon who does many meniscus repairs is likely to be more facile with the range of techniques necessary to treat these effectively than someone who only rarely does a meniscus repair.

A third thought is that some meniscus tears are much more likely to heal than others, and perhaps you are seeing a selection bias of tears that were of low likelihood to heal even under the best of circumstances. We know from other studies that generally about 70% of what we call peripheral meniscus tear repairs will heal successfully. These are the type with the best healing potential. In larger tears, such as a bucket handle tears, the success rate is around 55-60%. So you can see by these numbers, there is still a significant failure rate even in ideal circumstances.

I'm sure your observations are true- in fact they are probably what I would expect to see with respect to returning to activity more easily after a partial removal. The difficulty is that with partial removal, the 'rent doesn't come due' until years later. I have a number of patients referred to me who are in their 30's or 40's and had a meniscus removal in their teens or 20's and now have arthritis. This is an extremely challenging problem to solve.

Hopefully this lengthy (and likely rambling) post helps clarify the thought process. Your question is a very good one. If we knew in advance which tears would heal and which wouldn't, of course these decisions would be easier. Unfortunately, as I often tell patients, my crystal ball is a little murky.

So this is a very complex question/issue- I could probably do a two hour talk about it. No one wants to be inundated with that much ortho info by me, so I'll do my best to summarize.

As discussed in the article above, the meniscus is critical for normal function of many aspects of the knee. This includes stability, cushion and protection of the surface cartilage. Because of the importance of the meniscus, it is critical to try to preserve as much meniscus as possible, as often as possible in order to optimize the long-term function/health of the knee. For example, we know from studies that one of the biggest risk factors for ACL graft failure after reconstruction is having had part of your meniscus removed at the same time as reconstruction. We also know that the greater the amount of meniscus removed, the greater the risk that a person develops arthritis down the road.

Recall, arthritis is thinning or damage to the gliding surface cartilage of the knee (which is different from the meniscus itself). Once damage to the surface cartilage occurs, we don't have a great way to repair or restore the cartilage to normal. (There are some procedures that we have as options, but they are rarely as good as normal cartilage.)

Because of the lack of good options to treat arthritis, especially in young patients, we have become more aggressive over time at attempting to repair meniscus tears in order to prevent this problem.

With regards to stability, think of the meniscus as a chock that you place behind the wheel of a trailer that is parked on a hill to prevent it from rolling away. The meniscus helps stabilize the knee in the same way. As a result, when you remove part of the meniscus during an ACL reconstruction, there is a smaller 'chock' and therefor the ACL sees higher stress and is at greater risk to fail/re-tear.

In addition to our understanding of the function of the meniscus and its importance, we also have developed better tools to perform meniscus repairs more safely and easily.

As a result of the above factors, the number of attempted meniscus repairs has increased dramatically over the past 10-15 years. Any time you increase the number of procedures, the number of failures also increases (by sheer volume).

With respect to your specific examples noted in your post, I do have a couple of thoughts. One is, in young patients (particularly athletes) I am VERY aggressive with trying to repair any meniscus tear, because they are the patients that need their meniscus the most. If it fails, it is of course unfortunate, but removing meniscus that has a chance to heal is a bad idea, IMHO.

A second thought is that there could be some technical factors in play. Studies have shown that technique is critical in repairing these tears, and it is possible that some component of the failure is attributable to this. A surgeon who does many meniscus repairs is likely to be more facile with the range of techniques necessary to treat these effectively than someone who only rarely does a meniscus repair.

A third thought is that some meniscus tears are much more likely to heal than others, and perhaps you are seeing a selection bias of tears that were of low likelihood to heal even under the best of circumstances. We know from other studies that generally about 70% of what we call peripheral meniscus tear repairs will heal successfully. These are the type with the best healing potential. In larger tears, such as a bucket handle tears, the success rate is around 55-60%. So you can see by these numbers, there is still a significant failure rate even in ideal circumstances.

I'm sure your observations are true- in fact they are probably what I would expect to see with respect to returning to activity more easily after a partial removal. The difficulty is that with partial removal, the 'rent doesn't come due' until years later. I have a number of patients referred to me who are in their 30's or 40's and had a meniscus removal in their teens or 20's and now have arthritis. This is an extremely challenging problem to solve.

Hopefully this lengthy (and likely rambling) post helps clarify the thought process. Your question is a very good one. If we knew in advance which tears would heal and which wouldn't, of course these decisions would be easier. Unfortunately, as I often tell patients, my crystal ball is a little murky.